Mauro Henrique Moraes Vargas

Recombinant human deoxyribonuclease therapy improves airway resistance and reduces DNA extracellular traps in a murine acute asthma model.

ABSTRACT Purpose: Asthma is a highly prevalent chronic inflammatory lung disease characterized by airway hyperresponsiveness to allergens, airway edema, and increased mucus secretion. Such mucus can be liquefied by recombinant human deoxyribonuclease (rhDNase), in which efficacy of rhDNase has been well documented in patients with cystic fibrosis, but little studied in asthma. In the present study, we investigated whether rhDNase intranasal administration improved inflammation and pulmonary function in an experimental model of asthma. Methods: Mice were sensitized by two subcutaneous injections of ovalbumin (OVA), on days 0 and 7, followed by three intranasal challenges with OVA on days 14, 15, and 16. A control group, replacing OVA by DPBS, was included. On days 15 and 16, after 2 hours of OVA challenge, mice received 1 mg/mL of intranasal rhDNase. Results: We showed that rhDNase decreased significantly the airway resistance and reduced EETs formation and globet cells hyperplasia. Conclusions: Our results suggest that extracellular DNA in mucus play a role in lower airways obstruction in OVA asthma protocol and that the treatment with rhDNase improved lung function and DNA extracellular traps, with no direct cellular anti-inflammatory effects.

Extracellular DNA traps in bronchoalveolar fluid from a murine eosinophilic pulmonary response

Asthma is associated with a loss of the structural integrity of airway epithelium and dysfunction of the physical barrier, which protects airways from external harmful factors. Granulocyte activation causes the formation of extracellular traps, releasing web‐like structures of DNA and proteins, being important to kill pathogens extracellularly. We investigated whether eosinophils infiltrating airways in an experimental model of asthma would induce eosinophil extracellular traps (EETs) in bronchoalveolar lavage fluid and lung tissue. We showed that an ovalbumin (OVA) asthma protocol presented a significant increase in eosinophil counts with increased extracellular DNA in bronchoalveolar lavage fluid as well as in lung tissue, confirming the presence of DNA traps colocalized with eosinophil peroxidase. EETs formation was reversed by DNase treatment. With these approaches, we demonstrated for the first time that OVA‐challenged mice release extracellular DNA traps, which could aggravate pulmonary dysfunction.

Acute and chronic exposure to Tyrophagus putrescentiae induces allergic pulmonary response in a murine model.

Background Tyrophagus putrescentiae (Tp) is a source of aeroallergen that causes allergic diseases. Objective To describe an acute and chronic murine model of allergic asthma with Tp extract with no systemic sensitization and no use of adjuvant. Methods Mites from dust sample were cultured and a raw extract was produced. Female BALB/c mice (6-8 weeks) were challenged intranasally with Tp extract or Dulbeccos phosphate-buffered saline, for 10 consecutive days (acute protocol) or for 6 weeks (chronic protocol). Twenty-four hours after the last intranasal challenge, bronchoalveolar lavage fluid (BALF) was performed for total and differential cells count, cytokine analysis, and eosinophil peroxidase activity. Lung tissue was also removed for histopathologic analysis. Results Tp extract has shown a significant increase in total cells count from BALF as well as an increase in absolute eosinophils count, eosinophil peroxidase activity, interleukin (IL)-5 and IL-13 levels, in both acute and chronic protocols. Peribronchovascular infiltrate, goblet cells hyperplasia and collagen deposition were shown in the airways of acute and chronic Tp-exposed mice. Conclusion Our data suggest that the intranasal exposure to Tp extract, with no systemic sensitization and no use of adjuvants, induces a robust allergic inflammation in the lungs of mice, in both acute and chronic models. Our Tp extract seems to be a potent allergen extract which may be used in asthma model studies.

Clinical characteristics of children and adolescents with severe therapy-resistant asthma in Brazil.

Abstract Objective: To describe the clinical characteristics, lung function, radiological findings, and the inflammatory cell profile in induced sputum in children and adolescents with severe therapy-resistant asthma (STRA) treated at a referral center in southern Brazil. Methods: We retrospectively analyzed children and adolescents (3-18 years of age) with uncontrolled STRA treated with high-dose inhaled corticosteroids and long-acting ß2 agonists. We prospectively collected data on disease control, lung function, skin test reactivity to allergens, the inflammatory cell profile in induced sputum, chest CT findings, and esophageal pH monitoring results. Results: We analyzed 21 patients (mean age, 9.2 ± 2.98 years). Of those, 18 (86%) were atopic. Most had uncontrolled asthma and near-normal baseline lung function. In 4 and 7, induced sputum was found to be eosinophilic and neutrophilic, respectively; the inflammatory cell profile in induced sputum having changed in 67% of those in whom induced sputum analysis was repeated. Of the 8 patients receiving treatment with omalizumab (an anti-IgE antibody), 7 (87.5%) showed significant improvement in quality of life, as well as significant reductions in the numbers of exacerbations and hospitalizations. Conclusions: Children with STRA present with near-normal lung function and a variable airway inflammatory pattern during clinical follow-up, showing a significant clinical response to omalizumab. In children, STRA differs from that seen in adults, further studies being required in order to gain a better understanding of the disease mechanisms.

Protective effect of early prenatal stress on the induction of asthma in adult mice: Sex-specific differences.

Adversities faced during the prenatal period can be related to the onset of diseases in adulthood. However, little is known about the effects on the respiratory system. This study aimed to evaluate the effects of prenatal stress in two different time-points during pregnancy on pulmonary function and on the inflammatory profile of mice exposed to an asthma model. Male and female BALB/c mice were divided into 3 groups: control (CON), prenatal stress from the second week of pregnancy (PNS1) and prenatal stress on the last week of pregnancy (PNS2). Both PNS1 and PNS2 pregnant females were submitted to restraint stress. As adults, fear/anxiety behaviors were assessed, and animals were subjected to an asthma model induced by ovalbumin. Pulmonary function, inflammatory parameters in bronchoalveolar lavage (BAL) and histology were evaluated. There was a significant decrease in the number of entries and time spent in the central quadrant on the open field test for the PNS1 animals. Females (PNS1) showed improved pulmonary function (airway resistance, tissue damping and pulmonary elastance), significant increase in the percentage of neutrophils and lymphocytes and a decrease in eosinophils when compared to controls. There was a significant decrease in inflammatory cytokines in BAL of both males (IL-5 and IL-13) and females (IL-4, IL-5 and IL-13) from PNS1 and PNS2 when compared to the CON group. Prenatal stress starting from the beginning of pregnancy reduces the impact of asthma development in adult female mice, showing an improved pulmonary function and a lower inflammatory response in the lungs.

Equações internacionais superestimam a força muscular ventilatória em crianças e adolescentes com fibrose cística

El objetivo de este estudio fue comparar los resultados de la normalizacion de los datos de fuerza muscular ventilatoria utilizando tres ecuaciones de referencia internacionales y una nacional en ninos y adolescentes con fibrosis quistica (FC). Estudio retrospectivo, en el cual fueron incluidos pacientes con FC, edad entre 8 y 12 anos y control ambulatorio regular. Fueron colectados datos demograficos y variables antropometricas. Todos los pacientes incluidos deberian haber realizado test de fuerza muscular ventilatoria y espirometria en los ultimos 12 meses. La normalizacion de los resultados fue realizada utilizando las variables predictoras requeridas en cada ecuacion estudiada. Los datos fueron comparados utilizando una ANOVA de una via. Fueron incluidos 24 pacientes, 62,5% masculinos, media de edad 10,5±1,53 anos, estatura 138,0±0,08 cm, masa corporal 34,6±9,07 kg, VEF1 93,29±29,02% y CVF 103,78±26,12%. Las presiones (cmH2O) inspiratoria (PIMAX) y expiratoria (PEMAX) maximas encontradas fueron 92,1±22,8 y 98,9±24,5, respectivamente. Despues de la normalizacion por las diferentes ecuaciones, se demostro que las internacionales tienden a sobreestimar los hallazgos para nuestra poblacion. La ecuacion nacional presento valores medios previstos significativamente (p 100%) en 91,6, 79,1, y 75,0% de los sujetos y la PEMAX en 66,6, 87,5 y 50%, mientras la ecuacion nacional estimaria apenas 50,0 y 37,5% de los individuos, respectivamente. La normalizacion de los resultados de fuerza muscular ventilatoria en ninos y adolescentes entre 8 y 12 anos con FC utilizando ecuaciones internacionales sobreestiman los valores de las presiones respiratorias maximas.

Clinical characteristics, lung function and airway inflammatory patterns of Brazilian children with severe therapy-resistant asthma

Results 20 children with STRA (mean age: 11.3±2.9 years; 62% males) were included, and paired with 70 children with mild asthma and 27 healthy controls. 18/20 (90%) STRA children were atopic, and only 2/20 (10%) were sensitized to pets. Lung function from children with STRA was not different from the other groups studied. From 13 STRA children with induced sputum obtained, we have found seven, four and two neutrophilic, eosinophilic and paucigranulocytic patterns, respectively. The number/percentage of inflammatory cells and pattern of sputum inflammation were not different between children with STRA (n=13) and milder asthma (n=70). From 5 sputums repeated in STRA children, 4 (80%) had the inflammatory pattern changed. Six STRA patients are under omalizumab treatment. Conclusion Children with STRA have nearly normal lung function and their airway inflammatory pattern seems not to be different from children with milder asthma. The mechanisms involved in the uncontrolled disease of children with STRA are not clear and should be better addressed in future studies.

Traffic-related air pollution and black carbon in sputum macrophages: a “silent” lung disease?

Aims: To describe two case reports with significant black carbon deposition in sputum macrophages in healthy young adults from an urban city, showing mild airway obstruction in lung function tests. The role of black carbon deposition by air pollution in the airways and the development of indolent chronic lung disease in populations living in larger cities is not clear and may be a potential world health problem. Cases description: We report two cases of voluntary adults living in a South American large city who have undergone clinical examination, lung function and analysis of inflammation and black carbon deposition in macrophages from induced sputum. Two Caucasian, previously healthy, nonsmokers, male adults, living in the same city of southern Brazil, with no respiratory symptoms presented with normal physical exams, but with lung function demonstrating mild obstructive lung disorder, with no bronchodilator response. In particular, one of the subjects works daily in delivery services as a motorcycle driver. Induced sputum of both patients showed no signs of cellular inflammation. However, a large number of black carbon content was detected inside macrophages of the sputum sample in both patients. Conclusions: In summary, significant daily air pollution exposure may play a role in long-term silent disease in adults, potentially leading to clinically relevant chronic lung diseases later in life, particularly in populations of urbanized large cities from developing countries. The development of better, more directly and less invasive, methods for air pollution exposure are required, along with longitudinal studies, in order to measure the real impact of air pollution in chronic lung diseases of susceptible populations.

International equations overestimate the respiratory muscle strength in children and adolescents with cystic fibrosis

El objetivo de este estudio fue comparar los resultados de la normalizacion de los datos de fuerza muscular ventilatoria utilizando tres ecuaciones de referencia internacionales y una nacional en ninos y adolescentes con fibrosis quistica (FC). Estudio retrospectivo, en el cual fueron incluidos pacientes con FC, edad entre 8 y 12 anos y control ambulatorio regular. Fueron colectados datos demograficos y variables antropometricas. Todos los pacientes incluidos deberian haber realizado test de fuerza muscular ventilatoria y espirometria en los ultimos 12 meses. La normalizacion de los resultados fue realizada utilizando las variables predictoras requeridas en cada ecuacion estudiada. Los datos fueron comparados utilizando una ANOVA de una via. Fueron incluidos 24 pacientes, 62,5% masculinos, media de edad 10,5±1,53 anos, estatura 138,0±0,08 cm, masa corporal 34,6±9,07 kg, VEF1 93,29±29,02% y CVF 103,78±26,12%. Las presiones (cmH2O) inspiratoria (PIMAX) y expiratoria (PEMAX) maximas encontradas fueron 92,1±22,8 y 98,9±24,5, respectivamente. Despues de la normalizacion por las diferentes ecuaciones, se demostro que las internacionales tienden a sobreestimar los hallazgos para nuestra poblacion. La ecuacion nacional presento valores medios previstos significativamente (p 100%) en 91,6, 79,1, y 75,0% de los sujetos y la PEMAX en 66,6, 87,5 y 50%, mientras la ecuacion nacional estimaria apenas 50,0 y 37,5% de los individuos, respectivamente. La normalizacion de los resultados de fuerza muscular ventilatoria en ninos y adolescentes entre 8 y 12 anos con FC utilizando ecuaciones internacionales sobreestiman los valores de las presiones respiratorias maximas.

Ecuaciones internacionales sobreestiman la fuerza muscular ventilatoria en niños y adolescentes con fibrosis quística

El objetivo de este estudio fue comparar los resultados de la normalizacion de los datos de fuerza muscular ventilatoria utilizando tres ecuaciones de referencia internacionales y una nacional en ninos y adolescentes con fibrosis quistica (FC). Estudio retrospectivo, en el cual fueron incluidos pacientes con FC, edad entre 8 y 12 anos y control ambulatorio regular. Fueron colectados datos demograficos y variables antropometricas. Todos los pacientes incluidos deberian haber realizado test de fuerza muscular ventilatoria y espirometria en los ultimos 12 meses. La normalizacion de los resultados fue realizada utilizando las variables predictoras requeridas en cada ecuacion estudiada. Los datos fueron comparados utilizando una ANOVA de una via. Fueron incluidos 24 pacientes, 62,5% masculinos, media de edad 10,5±1,53 anos, estatura 138,0±0,08 cm, masa corporal 34,6±9,07 kg, VEF1 93,29±29,02% y CVF 103,78±26,12%. Las presiones (cmH2O) inspiratoria (PIMAX) y expiratoria (PEMAX) maximas encontradas fueron 92,1±22,8 y 98,9±24,5, respectivamente. Despues de la normalizacion por las diferentes ecuaciones, se demostro que las internacionales tienden a sobreestimar los hallazgos para nuestra poblacion. La ecuacion nacional presento valores medios previstos significativamente (p 100%) en 91,6, 79,1, y 75,0% de los sujetos y la PEMAX en 66,6, 87,5 y 50%, mientras la ecuacion nacional estimaria apenas 50,0 y 37,5% de los individuos, respectivamente. La normalizacion de los resultados de fuerza muscular ventilatoria en ninos y adolescentes entre 8 y 12 anos con FC utilizando ecuaciones internacionales sobreestiman los valores de las presiones respiratorias maximas.